Reduced suction and loud whistling noise from lid area of recovery tank.

Safety first: Unplug the machine before inspecting seals.

• Inspect gasket: Remove the recovery tank lid and examine the rubber gasket for splits, hardening, or flattening.
• Clean mating surfaces: Wipe the rim of the tank and the lid with a damp cloth to remove dirt and fibres.
• Check lid fit: Refit the lid, ensuring it is seated evenly all around. Listen for changes in noise when gently pressing on the lid during operation.
• Replace gasket: If the seal is damaged or does not compress evenly, replace it with the correct Numatic gasket.